 
#include <bits/stdc++.h>
    using namespace std;
int main() {
  double f;
  // cout << "请输入华氏温度：";
  cin << f;
  double c = (f - 32) * 5 / 9;
  cout << fixed << setprecision(2) << c << endl;
  return 0;
}

/*  

**[编译结果]**

[Error] no match for 'operator<<' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'double')

 */